In this study, a crystal plasticity finite element model (CPFEM) has been revisited to study the microstructure effects on macroscopic mechanical behavior of ultrafine-grained (UFG) nickels processed by severe plastic deformation (SPD). The microstructure characteristics such as grain size and dislocation density show a strong influence on the mechanical behavior of SPD-processed materials. We used a modified Hall–Petch relationship at grain level to study both grain size and dislocation density dependences of mechanical behavior of SPD-processed nickel materials. Within the framework of small strain hypothesis, it is quite well shown that the CPFEM predicts the mechanical behavior of unimodal nickels processed by SPD methods. Moreover, a comparison between the proposed model and the self-consistent approach will be shown and discussed.